In the manufacture of printable sheets such as business forms and children's play mats, there are many circumstances in which it is desirable to form an integral, but ultimately separable, self-adhesive label as a part of the printable sheet. There are also many circumstances in which it is desirable to print on the self-adhesive label.
Conventional methods for the manufacture of printable sheets with integrated labels require either a) lamination of two webs of material, one for printing and the other to provide a backing for the label, or b) direct adhesion of a label laminate (label/adhesive/release layer/support) to the form. There are many variations of these two techniques. Where a label laminate is adhered to a paper sheet of a business form, it is typically applied on top of the paper sheet or edge thereof. See, for example, U.S. Pat. Nos. 4,865,669, 4,809,905 and 5,129,682. For the lamination techniques, a pressure-sensitive adhesive is typically applied to a portion of a paper sheet (first web) followed with a backing comprised of paper or similar material (second web) coated with release liner. A label is then cut from the paper sheet where the backing has been applied. Application of the pressure-sensitive adhesive and backing material with release liner is often accomplished simultaneously with the use of a transfer tape. The transfer tape is applied to the rear face of the paper sheet with the adhesive contacting the rear face of the paper sheet. Once the transfer tape is applied, the pressure-sensitive adhesive transfers from the tape to the paper sheet. Other examples of laminating techniques used to produce business forms with labels integrated therein are described in U.S. Pat. Nos. 5,240,153, 5,507,901, 5,632,842 and 5,656,369. These laminating techniques, as well as methods for direct adhesion of labels to a form, require complex paper handling apparatus which must either align and adhere a label laminate to a paper sheet or align and adhere a paper sheet (first web) with a backing (second web) to provide the integrated label. In addition, where a second web is used, there is an increased risk of paper jams in printing equipment due to the increased thickness of the printable sheet at the label. There is also a risk of loss of the backing (second web) during printing or handling, resulting in exposure of the adhesive. Certain methods have specialized problems as well, for example, forms made with the use of transfer tape also have a tendency to curl and additional care is needed to flatten these forms.